Cummins/Onan FM-JFE2 — Carburetor Adjustment
Adjustments
For the Cummins/Onan FM-JFE2, from the Cummins/Onan service manual.
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Before you start
- Use proper size screwdriver to avoid burring or distorting jet
- Never use wire to clean brass jet
Procedure
- Run plant approximately one-half hour before changing adjustment.
- For idle: turn idle jet needle right until engine nearly stops.
- Open slowly to position where engine runs smoothest; usually 1/2 to 1-1/4 turns open.
- For main jet: turn needle out 4 or 5 turns to enrich.
- Turn slowly in clockwise until plant begins to lose speed and power.
- Open slowly until plant regains maximum power and speed.
- Never open jet over one half turn from efficient point.
Tools required
- screwdriver Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Idle jet 1/2 to 1-1/4 turns open
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.